Area Forecast Discussion
Issued by NWS Medford, OR

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FXUS66 KMFR 221611

Area Forecast Discussion
National Weather Service Medford OR
911 AM PDT Thu Jun 22 2017

.DISCUSSION...The main two issues continues to be the heat and
winds offshore. The Chetco Effect is in full swing with the
overnight low in Brookings only dipping into the mid 70s. The
forecast continues to show 95 for Brookings. I`m troubled by the
wind swing to the northwest. That would limit heating today. Will
continue to monitor for possible update. For inland areas, the
heat cranks up Friday and really gets going on Saturday. The
thermal trough continues to build Friday that will raise
temperatures for the western valleys and Siskiyou County. On
Saturday, the thermal trough moves inland to bring the hottest day
of forecast period. I`m evaluating the morning guidance and will
likely bump up temperatures a little bit. Heat advisories and
excessive heat warnings will come out today for Saturday and may
linger into Sunday. The morning low temperatures for the weekend
will be in the mid to upper 60s which limits the overnight relief
from the heat. All areas east of the Cascades will be quite warm
but not to advisory levels.

Moisture from a closed upper low off of California is still
expected for later Sunday and into the first of the week. This
will bring a slight chance of thunderstorms to many areas. The
possibility of lightning following the heat wave may increase
fire risk across the area. JBL


.AVIATION...22/12Z TAF CYCLE...Mostly VFR across the area for the
next 24 hours. Strong northerly winds are expected again today at
KOTH with wind gusts of 35-40 kt developing in the
afternoon/evening. -Sven


.MARINE...Updated 830 AM Thursday, 22 June 2017...An unusually
strong thermal trough will prevail over the south coast into Friday,
causing steep, wind driven seas and gale force north winds. The
strongest winds and steepest seas will occur during the afternoons
and evenings south of Cape Blanco...but even northern portions of
the waters will have strong winds (occasional gale force gusts) and
warning level hazardous seas through tonight. Conditions will
gradually improve this weekend with conditions dropping below
advisory levels by Saturday morning. Southerly flow and fog are
expected Saturday night into Sunday.


.PREV DISCUSSION... /Issued 320 AM PDT Thu Jun 22 2017/

DISCUSSION...The heat is on. Very hot temperatures will impact
areas from west to east over the next several days, starting with
a heat advisory for the Chetco area of the Curry County coast
today. Highs will likely reach 90 or above in Brookings again
today, following lows this morning in the mid to upper 70s. The
thermal trough will strengthen and begin to slide inland this
weekend. While this will mean relief for the southern coast, where
south winds will bring a surge of clouds and cooler temperatures
late Friday into Saturday, the inland areas will continue to warm
significantly. Triple digit highs will likely be common Saturday
and perhaps SUnday as well for the West Side, with all inland
areas seeing highs 20 to 25 degrees above normal for this time of
year. With overnight lows this weekend remaining relatively warm
as well, heat headlines may be necessary for the Rogue and
Illinois Valleys, as well as the valleys of Siskiyou County.

Relief for the rest of the forecast area will arrive late in the
weekend, as an upper level trough slowly pushes into the coast.
Shortwaves in the flow ahead of the trough may be enough to kick
off convection over much of the area Sunday afternoon through
Monday evening, but the timing and location of these storms is
still uncertain. Whether or not thunderstorms do develop,
temperatures will see a marked cooling trend early next week,
dropping to near normal values for the rest of the forecast term.


OR...Heat Advisory until 9 PM PDT this evening for ORZ022.


Pacific Coastal Waters...Small Craft Advisory until midnight PDT Friday night for
     Gale Warning until midnight PDT Friday night for PZZ356-376.
     Hazardous Seas Warning until midnight PDT Friday night for

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